The use of printed circuit board assemblies mounted in shelves is well known in electronic systems. Typically these printed circuit board assemblies are oriented vertically and disposed adjacent to each other across the width of the shelf. The vertical disposition facilitates cooling via air flow, either convective or forced, and facilitates access to the separate assemblies independent of each other.
These assemblies typically comprise printed circuit boards with interconnecting conductive traces for components mounted thereon, and a connector for connection to a backplane or midplane. The components and their compatible connectors are typically electronic and optical in nature. These printed circuit board assemblies normally have a faceplate disposed at the outermost edge of the printed circuit board, opposite the edge having the connectors which interface with the backplane or midplane.
The faceplate may be engineered to provide a variety of mechanical functions, such as stiffening or a mounting point for ejectors providing mechanical leverage for removing the assembly from the shelf; as a mounting point for components such as displays, switches and connectors; and as a component of electrical functions such as one portion of an EMC/RFI shield for the assembly.
As the servicing and cleaning of optical fibers and connectors at a backplane or midplane can present certain physical access difficulties, a faceplate is a preferred mounting point for optical connectors. As may be apparent, the quantity of such components is limited by the mounting area provided by the faceplate. Attempts to increase connector density by decreasing the size of the pluggable media are limited by standard form factors for commonly used media, whereas attempts to increase the faceplate area are limited by the shelf height and given printed circuit board assembly spacing across the shelf.
In view of the foregoing, it would be desirable to provide a means for increasing the quantity of connectors available at the faceplate which overcomes the above-described inadequacies and shortcomings but works within the dimensioning constraints of standard shelf and connector practices.